Analysis of characteristics and development trend of filling mining technology

In the mining process, after the ore body is mined, a certain goaf area will be formed in the mining area, which will have a great impact on the subsequent mining work and the surrounding geological environment. The core idea of ​​the filling mining process is to replace the mined body with a certain filling during the mining process to compensate for the bearing capacity of the goaf, reduce the damage to the goaf, and improve the safety of mining operations. [1-3]. This study analyzes the characteristics of the process in detail and discusses its development trend to provide reference for related applications.
1 filling method

(1) Dry filling. The filling of the goaf is mainly carried out by dry packing such as sand and waste rock, which is the earliest filling method used in mining. When using dry filling method for mining, the problems to be noted are: 1 mining should maintain continuity, that is, mining operations should not be interrupted; 2 for dry filling, filler wells should be set; 3 packing process should be based on actual conditions The situation is layered and filled, and the layers can be separated by materials such as firewood sticks and jingba to enhance the stability of the filling body.
(2) Water sand filling. Water sand filling is more compact than dry filling. Under normal circumstances, water sand filling is the use of slag, sand, tailings and other materials mixed into solid-liquid two phases, pumped into the well to fill the gob. When filling the water sand, pay attention to the following points: 1 When preparing the filling, it should be carried out through the mixing chamber, using advanced mechanical equipment to realize the automation and precision of the mortar preparation process; 2 when preparing the mortar, according to the gob area The actual situation is reasonable to determine the water-sand ratio; 3 to build an automated feeding platform to improve and stabilize the feeding speed of the filling, to ensure that the filling effect is in line with expectations.
(3) Cementation filling [4]. Cement filling is a kind of goaf filling method different from dry filling and water sand filling. It mainly uses cement material to make gravel, aggregate or river sand into colloid by mixing and pumping cement through pipeline. Send to the gob for filling. In recent years, the cement filling technology has made great progress, and there are many cementing filling processes for different materials, such as tailings cement filling, block cement filling, and paste pumping filling. The tailings cementing filling process mainly uses the coarse aggregate to prepare the filling cement, although the process has appeared in the 1960s, and it was not popularized because of the difficulty in meeting the preparation requirements of the cement at that time. In the era, the fine sand colloid completely replaced the coarse aggregate colloid, which promoted the rapid development of the process.
2 filling mining process characteristics
2.1 Advantages
(1) The filling mining process has high flexibility, and the mining and cutting work is small. For underground mining operations, the smaller workload and higher flexibility have greater application advantages.
(2) Using the filling mining process for mining, the secondary utilization of the waste rock and other materials can not only reduce the transportation cost of the materials, but also reduce the maintenance cost of the goaf.
(3) During the mining process, as the ore body is gradually extracted, the stability of the goaf will be greatly reduced, jeopardizing the subsequent normal operations. Filling in time after the ore body is produced can effectively prevent the roof of the roadway from falling, strengthen the mechanical properties of the surrounding rock, enhance the stability of the goaf, and provide a good safety guarantee for the subsequent mining operations.
(4) For mining bodies with thin ore bodies or mines with multiple quality ores, mining operations can be carried out by means of sorting and mining, which can achieve efficient mining.
(5) During the mining process, due to the presence of dust and some flammable and explosive gases, it will pose a certain degree of safety threat to mining operations. By effectively filling the goaf, the dust and flammable and explosive gases in the goaf can be effectively reduced, and the possibility of fire in the mining process can be effectively reduced.
(6) In the mining process of the ore body, the use of tailings or waste rock to fill the mining area can not only improve the mining rate of the ore body, but also effectively utilize various types of waste rock generated during the mining process to reduce the waste rock treatment. Invest.
(7) By applying the filling mining process, surface subsidence can be effectively controlled, the stability and safety of the mining area can be improved, the underground working environment can be greatly improved, and the safety of workers can be improved.
2.2 disadvantages
(1) The actual operation process of the filling process and the recovery section of the filling mining process is complicated. In the mining process of the ore body, it will cause a lot of difficulty for the mining operation, which may lead to a substantial increase in the cost of mining operations or a significant drop in mining efficiency.
(2) Filling operations and mining operations are carried out at the same time, and the two are bound to affect each other, which reduces the efficiency of mining operations to a certain extent.

(3) Filling mining process In the actual application process, due to the low degree of mechanization, compared with other mining processes, the mining efficiency is lower and more time-consuming, which makes the mining operation efficiency and capacity difficult to meet the progress requirements of mine production. .
(4) There are many types of filling mining processes. If some new filling processes are used, the use of artificial mixing materials for filling, not only need to send waste rock and waste generated by mining, but also need to purchase raw materials to prepare filling, so that the mining cost is large. The rise has greatly reduced the economic benefits of mining companies.
3 development trend
(1) Filling optimization. The filling is the core of the filling mining process. The dry filling method uses gravel, waste rock, etc. for filling. Although the cost is low, the overall integrity is not good, and the overall bearing capacity of the filling is low, which is difficult to meet the requirements of safe mining of the mine. The cement filling method can improve the integrity of the filling and enhance the filling performance, but it increases the mining cost to a certain extent and reduces the economic benefits of the enterprise. To this end, through the development of new consolidation materials, to replace the traditional cement slurry, and constantly upgrade the physical and chemical properties of the filling [5], further reducing mine production costs.
(2) Mechanization and automation. In the application process of filling mining technology, a large amount of filling material needs to be transported to the goaf for filling operation. At present, the level of mechanization and automation of domestic downhole filling is still not high. In this regard, 1 automation and intelligent design of mining machinery, through the advanced information technology and remote control technology, install various types of sensors on mining machinery equipment, using computer systems to form automation control. 2 Build a comprehensive inspection system to detect dust, gas, temperature, humidity and other indicators for all aspects of mining, especially pay attention to real-time monitoring of goaf, for surrounding rock changes and surface subsidence Early warning. 3 Effectively coordinate the process of mining and filling, so that it can be alternately and orderly, reducing the interaction between the two and ensuring the automation of mining [6].
(3) Improved filling method. The current filling method mainly uses a pipeline pump to feed the filling material into the goaf. This filling method is likely to cause serious wear of the components of the pipeline pump when conveying some filling materials, scale formation inside the pipeline, and the filling efficiency is greatly reduced. In this regard, the high temperature can be used to maintain the fluidity of the filling, reduce the fouling phenomenon, and the high pressure can be used to enhance the thrust, so that the filling can be completely sent into the gob. In addition, it is necessary to ensure that the filling and mining operations can be carried out simultaneously.
(4) New cementitious materials [7-9]. New cementitious material mainly composed of silicon oxide, aluminum oxide, iron oxide, calcium oxide, magnesium oxide, a mixture consisting of a specific surface area of more than 3900cm2 / g, density of 3t / m3, the overall performance of alkaline. In recent years, new types of cementitious materials have developed rapidly, and the distribution ratio has been continuously optimized and upgraded, and the performance has been significantly improved.
Through the comprehensive analysis of fuzzy indicators, different dimensions and quantifiable indicators, the new cementitious materials show superior performance compared with traditional filling materials, and the application prospects are better.
4 Conclusion
The basic principles of dry filling, water sand filling and cementing filling were analyzed respectively. The advantages and disadvantages of filling mining technology were summarized. On the basis of this, the development trend of the process was analyzed and it was considered that the new cementing material was It has good performance and is an important direction for the development of filling mining technology.
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